A continuing challenge is to optimize the power and fuel economy of a four-stroke opposed-piston engine. A related challenge is to reliably ignite a fuel-air mixture within a combustion chamber within a four-stroke opposed-piston engine. Historically, increasing the relative power of an opposed piston engine has been restrained by the fact that most, if not all, earlier designs of opposed piston engines were two-stroke engines. Recent advents in the design of opposed-piston engine technology includes providing four-stroke technology in context with the opposed-piston combustion chamber design. One related challenge has been to increase the combustion chamber volume to thereby increase the fuel-air mixture and as such, increase the power output produced upon combustion. To that end, it is critical that the combustion chamber realize increased fuel-air mixtures, along with enhanced means to ignite this mixture.